An image forming apparatus refers to an apparatus that prints an image on a printing medium, e.g., paper, according to an input image signal. An image forming apparatus may generally be classified as a printer, a copying machine, a fax machine, a multi-function printer, which includes multiple functions of printing, scanning, copying and/or faxing, and the like.
An electrophotographic type image forming apparatus generally includes an exposure device, a transfer device, a developing device, a fusing device and a main body, which defines a general exterior appearance of the image forming apparatus, and which accommodate one or more of the above components.
A printing medium, carrying on the surface thereof a quantity of developer forming the image, is subjected to a high temperature and/or high pressure while passing through a fusing device, so that the developer image is fused to the printing medium.
A transfer device transfers a visible developer image formed on an image carrier to a printing medium, in some cases by first transferring the image to an intermediate transfer body, from which the developer image is re-transferred to the printing medium.
However, a conventional image forming apparatus employing an intermediate transfer belt as the intermediate transfer body is configured such that even when it is in a non-operating state, i.e., in a stand-by state, the intermediate transfer belt may still be in the stretched state retaining a certain level of tensile force, which may result in shortening the life of the intermediate transfer belt.
Also, even When a black and white image is being printed with a conventional image forming apparatus, not only the image carrier for the black color, which is involved in the image transfer, but also those image carriers of other colors, which are not involved in the image transfer operation, are nevertheless also in contact with the intermediate transfer body. Such unnecessary contacts between the intermediate transfer body and the image carriers may contribute to the shortening of the life of the intermediate transfer body.
It would therefore be desirable to provide in an image forming apparatus the feature(s) of controlling the tension of the intermediate transfer body and/or the contacts between the image carriers and the intermediate transfer body, and more preferably that such feature(s) are provided in a manner allowing efficient space utilization.